not for nothing, but as a salesperson I recommend you should buy your car off the internet from gm. then you will not make some struggling car salesman work his ass off only for you to tell him you know what invoice is and eliminate any possibility of him making a commission. Not being a jag, just a struggling salesman. I usually tell people after I earn the right to ask for there business that I will wright the deal up at a couple hundred over invoice, I do not think that is out of line. Most stores will whore there cars out at the cost of standing behind there product or forgetting who you are after the sale. Find a salesman that treats you right and you like, allow him to make a commission and he will go to bat for you when you need it. He is not going to put his kids through college on you, maybe 75 to 150 bucks. Not trying to be an a hole here, just looking to save some salesman an afternoon beating, edmunds kills us with inaccurate invoices! sorry for the rant! gm has killed us with reducing the mark up over the years. soon it will be like buying from best buy, some pimpled 17 year old who does not care what you want nor does he know anything. Find a good store who will show you there invoice and treat you right. best of luck.